This article systematically reviews the literature on the effects of adverse life events or trauma on people with intellectual disabilities. It is important to systematically examine empirical evidence of the effects of trauma in people with intellectual disabilities as to date the number of studies in this area is not substantial, and the effects of trauma seen in the predominately general population literature are not necessarily transferable to the intellectual disability population. Identification of the effects of trauma on people with intellectual disabilities facilitates case recognition and appropriate treatment. Fifteen articles were selected for the review, and the results suggest that studies to date have been hampered by the lack of a consistent definition of trauma and the lack of a reliable and valid means of measuring the effects of trauma in people with intellectual disabilities. The review also indicates a lack of studies establishing causal links between life events and trauma.